Generally, a vehicle fuel supply device includes a fuel tank in which fuel is stored, a fuel pump, which pumps the fuel stored in the fuel tank to supply the fuel to an engine, a fuel filter, which removes foreign substances included in the fuel to be supplied to the engine, and a fuel line, which transports the fuel.
As an example of the vehicle fuel supply device, a liquefied petroleum gas (LPG) vehicle that uses LPG fuel includes an LPG bombe, which corresponds to a fuel tank, and a fuel pump is mounted in the bombe to deliver the LPG fuel to the engine side.
Hereinafter, a further description will be made with respect to a liquefied petroleum injection (LPI) fuel supply device of the LPG vehicle. A conventional LPI fuel supply device basically includes, for example, an LPG bombe in which LPG fuel is stored, a fuel pump, which delivers the LPG fuel stored in the bombe, a controller for driving and controlling the fuel pump, a fuel supply line, which supplies the fuel delivered by the fuel pump to an injector of an engine, a fuel return line for collecting unused fuel from the engine and returning the same to the bombe, and a regulator valve provided on the fuel return line.
In the configuration described above, the bombe is usually mounted inside a trunk room in the LPG vehicle, and the fuel pump is mounted inside the bombe.
In the vehicular fuel supply device, the controller for driving and controlling the fuel pump may be provided on one side of the fuel tank, for example, on one side of the LPG bombe, and more particularly, may be provided on a mounting member, such as a flange, a fuel pump plate or a bracket, fixed on one side of the LPG bombe.
The fuel pump controller may include a motor driver for feedback control of the driving of the fuel pump (i.e. a pump motor), electric wires, and connectors, and the motor driver may have a configuration in which elements for driving the fuel pump, such as switching elements (e.g., FETs) and condensers, are mounted on a printed circuit board (PCB).
The motor driver drives and controls the pump motor upon receiving signals output from an electronic control unit (ECU) depending on engine operating conditions. For example, when the motor driver receives a pulse width modulation PWM signal, switching elements of an inverter are driven in response to the PWM signal to convert direct current into three-phase alternating current, and the pump motor is driven upon receiving the three-phase alternating current output from the motor driver.
At this time, the speed in revolutions per minute (RPM) of the pump motor may be controlled in several stages based on the PWM signal.
In the fuel pump controller, the connectors may include, for example, a power supply connector, a signal input/output connector, and a connector for outputting the three-phase alternating current converted by the switching elements of the inverter to the pump motor.
In the fuel supply device described above, the fuel pump controller may control the stepwise supply of fuel to the engine by adjusting a rotational speed (RPM) of the fuel pump based on the engine operating conditions. At this time, since the controller continuously consumes power, a large amount of heat is generated from, for example, the printed circuit board (PCB).
Therefore, although cooling is necessary to protect, for example, the internal circuit of the motor driver, the related art provides no cooling device to cool the controller, which deteriorates the durability of the controller.
Meanwhile, in order to prevent fuel loss and air pollution, the vehicle is provided with a canister, which collects and stores fuel evaporation gas generated from the fuel tank.
The canister is configured by filling a case having a predetermined volume with an absorbent material capable of absorbing hydrocarbons of fuel evaporation gas generated from the fuel tank (e.g. a gasoline fuel tank). Activated carbon is widely used as the absorbent material.
The activated carbon in the canister functions to adsorb a fuel component of the fuel evaporation gas introduced into the case, such as hydrocarbons.
While the engine stops, the fuel evaporation gas (more particularly, a fuel component such as hydrocarbons) is adsorbed onto the activated carbon in the canister. Then, when the engine is driven, the fuel evaporation gas adsorbed on the activated carbon is separated by the pressure of air suctioned from the outside. The separated fuel evaporation gas is supplied, along with the air, to an intake system of the engine.
An operation of supplying the fuel evaporation gas from the canister to the engine is generally referred to as a purge operation. The fuel evaporation gas generated from the fuel tank is collected in the canister and is then purged to the engine intake side via a purge control solenoid valve (PCSV) so as to burn in the engine during engine driving.
Now, the general configuration of the canister will further be described. The canister includes the case defining an inner space having a predetermined volume and filled with activated carbon, and the case has several ports, such as a purge port that is connected to the engine intake system for the discharge of the collected fuel evaporation gas to the engine side, a loading port that is connected to the fuel tank for the introduction of the fuel evaporation gas, and an air port that is connected to an air filter for the suction of air.
In addition, the case includes a partition formed in the inner space thereof to separate a space in which the air port is located from a space in which the purge port and the loading port are located. As the fuel evaporation gas introduced through the loading port passes through the inner space divided by the partition, hydrocarbons, which are a fuel component, are adsorbed onto the activated carbon.
When the PCSV, which is controlled by the ECU, is opened during engine driving so that a suction pressure, i.e. a negative engine pressure is applied from the engine side to the inner space of the canister through the purge port, air is suctioned through the air filter and the air port, and the fuel evaporation gas and the hydrocarbons, which are separated from the activated carbon by the air, are discharged through the purge port to thereby be introduced into the engine.
For such a purge operation of causing the air to be suctioned into the canister and causing the fuel component, such as hydrocarbons, to be separated from the activated carbon inside the canister by the suctioned air to thereby be suctioned, along with the fuel evaporation gas, into the engine, the negative engine pressure needs to be applied to the canister through a purge line and the purge port.
However, in the interests of improved fuel efficiency, the number of engine purge operations tends to be decreased, and in particular, in the case of a continuously variable valve lift (CVVL) engine or an HEV/PHEV engine, the number of purge operations must be reduced due to a reduction in the engine negative-pressure area.
In the related art, since there is no solution to increase purge efficiency despite a reduction in the number of purge operations and no external energy is applied to increase purge efficiency, purge efficiency is poor and has difficulty in satisfying evaporation gas regulations.
Therefore, there is an urgent demand for a solution to increase the efficiency of a purge operation in consideration of the reduction in the number of engine purge operations.
In addition, in the related art, the canister air filter has been separately mounted on a specific position of the vehicle, such as a filler neck, and, for example, a bracket or some other fastening member is required to fix the air filter to the filler neck, which increases the number of elements and the production costs.